Transport network with high transmission capacity for telecommunications

ABSTRACT

A transport network with a transmission capacity for telecommunications in which nodes of the network are transparently connected with one another by optical glass fiber lines functionally to produce a full intermeshing of nodes permitting simultaneous addressing of all the nodes by every other node of the network. The nodes are coupled with one another in a matrix configuration in lines and columns. Each of corner nodes has at least n connections in the column direction and at least m connections in the line direction. Intermediate nodes (1,2 to 1,(m-1); n,2 to n,(m-1)) that are located in marginal lines, in a direction of the columns, have n connections and in a direction of the lines have 2·m connections. The intermediate nodes (2,1 to (n-1),1 and 2,m to (n-1),m)) located in marginal columns, in a line direction, have m connections and, in a column direction, have 2·n connections. Inner nodes of the network are connected with each of four neighbors by a total of 2·m connections, in the line direction, and 2·n connections, in the column direction. Individual nodes are addressable by at least one line and/or one column.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a transport network with a high transmissioncapacity for telecommunications, in which nodes of the network aretransparently linked with one another by optical glass fiber lines insuch fashion that a complete functional intermeshing of the nodes isproduced that permits simultaneous addressing of every node by everyother node in the network.

2. Description of the Prior Art

Such a network is known in the form of a fully intermeshedwavelength-multiplex network with a Star topology (H. Kobrinski,"Crossconnection of Wavelength-Division-Multiplexed High SpeedChannels," IEE Electrical Letters, Volume 23, pp. 975-977, Aug. 27,1987).

In this known network, every node can be addressed by every other nodethrough a central node. The disadvantages of this network configurationare the following: in the event of failure of one of the transmissionlines between the individual nodes and the central node, communicationwith other network nodes is completely interrupted for this node. Datastreams from other network nodes cannot be received by this node, norcan data streams be transmitted to other network nodes. In the event offailure of the central node, no communication whatever is possible anylonger between individual network nodes. In addition, a seriousdisproportion can exist between the Euclidean intervals of a node andthe nodes adjacent to this node and the transmission line lengths alongthe optical fiber link through the central node to these nodes.

The goal of the invention is therefore to improve a functionallycompletely intermeshed telecommunications network of the species recitedat the outset in such fashion that its sensitivity to the failure ofindividual nodes is significantly reduced and the drastic disproportionsbetween the Euclidean distance and the fiber-optic transmission linesbecome much more favorable.

The network configuration of the invention achieves at least thefollowing functional properties and advantages:

The network configuration according to the invention in matrix topologylinks every node in the network with at least its two neighbors andthus, in the event of failure of one of the glass fiber cable linksconnecting the nodes, rerouting the data streams through the remainingconnections. For static or approximately static and equally distributedincreases in data traffic, full intermeshing provides the largest usabletransmission capacity since no transmission capacity need then beprovided for the functions of a protocol, to regulate the distributionof the entire transmission capacity of the network at the individualnodes. The functional full intermeshing of this network with matrixtopology is achieved by using various optical fibers along a line toaddress the column of an addressed node and a signal identifier foraddressing the line of the same addressed node, the use of a number oftransmitters and receivers that corresponds to the number of networknodes, and a permutation of the signal identifiers used for addressingalong the lines and columns to avoid collisions. Due to the fact thatthe signal path of a data stream runs only along the line of thetransmitting node and along the column of the receiving node, in anetwork with regular matrix-type nodes the ratio between the length ofthe fiber optic transmission line and the Euclidean distance betweentransmitting and receiving nodes is less than or equal to the squareroot of2.

An addressing space is used that consists exclusively of a number ofdifferently defined wavelengths that corresponds to the number ofnetwork nodes. This offers the advantage that a modulation format can befreely chosen for each of the transmission paths in the network that arespecified only in the wavelength.

An addressing space is used that consists exclusively of a number ofdifferently defined periodic time slots that corresponds to the numberof network nodes at which the corresponding transmitter and receiver areready to receive. Operation can proceed with only one wavelength, but itrequires synchronization of the transmitters and time-multiplexers ofthe individual network nodes with one another.

An addressing space is used that consists of various wavelengths as wellas time windows or time slots that recur in a periodic sequence. Thisoffers the advantage that for a number of network nodes that is toolarge to use a corresponding number of wavelengths that are different bydefinition, a sufficiently large addressing space can nevertheless beformed.

The advantage of the matrix-type structure for linking the network nodeswith one another, permits a "detour" of data streams in both the opticaland electrical ranges in the event of failure of parts of the network.

Protection paths occur in the electrical area and through a plurality ofnetwork lines that are not affected by damage and the advantage isobtained of having a control of the protection paths that is both simpleand flexible.

The network nodes have a uniform structure of wavelength multiplexersand wavelength demultiplexers and a programmable structure composed ofwaveguides, optical transmitters and receivers, these node structuresare suitable for electro-optical integration.

Use of optical semiconductor amplifiers (SOA) in the waveguide includedin the node structure, makes use of the fact that only light fluxes ofone wavelength propagate along these waveguides. The simultaneousamplification of only one wavelength at a time is necessary since strongsaturation-induced crosstalk in the optical semiconductor amplifier doesnot permit any other type of operation. However, as it is the case here,when light fluxes of only one wavelength propagate along the waveguide,advantage can be taken of the optical semiconductor amplifier thatpermits regenerative pulse shaping of the modulation pulses propagatingalong dispersive fibers.

Use of a combination of wavelengths and time slots to form the addressspace signify that the data streams of one line coming from differentcolumns and transmitted by different wavelengths can be brought togetheronly by power dividing elements and the advantage is obtained that thetransmitting and receiving elements of the various nodes do not have tobe synchronized with one another.

The goal stated initially and forming the basis of the invention is thateach of the corner nodes (1,1; 1,m; n,1 and n,m), looking in the columndirection, has at least 2·(n-1) connections and in the line directionhas at least 2·(m-1) connections, and the intermediate nodes (1,2; . . .;1,j; . . . ;1,(m-1) and n,2; . . . ;nj; . . . ;n,(m-1) with j=(2;3; . .. ; m-1)) located in the marginal lines, looking in the columndirection, have at least 2·(m-j)·j+2·(m-j+1)·(j-1) connections and theintermediate nodes located in the marginal columns (2,1; . . . ; i,1; .. . ;(n-1),1 and 2,m; . . . ;1,j; . . . ;(n-1),m) with i=(2;3; . . . ;n-1)), looking in the line direction, have at least 2·(m-1) connectionsand, looking in the column direction, has at least2·(n-i)·i+2·(n-i+1)·(i-1) connections and the inner nodes (i,j withi=(2;3; . . . ;n-1) and j=(2;3; . . . ;m-1)) of network (10) areconnected with each of their four neighbors by a total of at least2·(m-j)·j+2·(m-j+1)·(j-1) connections, looking in the line direction,and with at least 2·(n-i)·i+2·(n-i+1)·(i-1) connections, looking in thecolumn direction. Because the number of glass fibers along the lines andcolumns between two nodes of the network is proportional to the sum ofthe channels required for functional full intermeshing, the capacityutilization of all the fibers is maximized by a load that is evenlydistributed through the fibers.

An addressing space is provided that consists of a number of wavelengthsthat are different by definition and that corresponds to the larger ofthe number of nodes of a line m and the number of nodes of a column n.This has the advantage that for each of the transmission paths in thenetwork, specified only by wavelength, a modulation format can be freelychosen, yet only a number of wavelengths smaller than the number ofnodes in the network is required. For the "quadratic" case (m=n), thenumber of wavelengths defined as different that are required correspondsonly to the square root of the number of nodes. Another advantage isachieved by the fact that at each node in the network that can beaddressed in this fashion, with the exception of the wavelength marked"I", each of the max(m,n) wavelengths defined as different is assignedto exactly m·n/max(m,n) transmitters as the emission wavelength and toexactly m·n/max(m,n) receivers as a receiving wavelength, with thepossibility of using laser diodes and photo diode arrays that arepreferably operable at max (m,n) wavelengths. The number of transmittersand receivers in each node associated with wavelength "I" is nearlym·n/max(m,n), namely (m·n/max(m,n))-1.

For each node in the network according to the invention, a structurethat is identical for all the nodes is used, to which structure thosefibers are connected that carry light fluxes that lead to the column ofthe node, as well as those fibers that support the light fluxes that aredirected from this node to the other columns in the network. All otherfibers are merely looped through. As a result of the uniformity of thenode structure, the first advantage is obtained, namely that the nodescan be manufactured in large numbers and thereby can be providedeconomically, as well as the second advantage, namely that the structureis especially suitable for electro-optical integration. This structure,which is identical for all the nodes, includes the various wavelengthsfor distribution of the light fluxes that come from the line of a nodeto the fibers of the column of this node, has the necessary structure ofa "WDM-Cross-Connects" mentioned at the outset. This structure of the"WDM-Cross-Connects" within all the nodes of the network according tothe invention thus constitutes a basic structure whose expansion in thedesign of the network according to the invention can be referred to as"WDM-Gridconnect."

The encoding of the addressing in the wavelength of each node isidentical when the rule is applied, first along the line and then alongthe column, for selecting the signal path and, when the rule is appliedto select the signal path first along the column and then along theline, offers the advantage that the network according to the invention,without changing the node structure, can be switched to a state withmodified signal paths only by switching the connections to the nodestructure used. As a result, it is possible to switch thealready-mentioned spatially disjointed protecting paths for signalswhose path has been interrupted by a failure, in the optical range forlight fluxes, which change along the path from their transmitting nodesto their receiving nodes and change the column as well as the line ofthe network.

The network can be expanded by virtue of the fact that the nodes ofcolumns j and j+1 are connected pairwise with one another with fouradditional fibers in the line direction, with, for even numbered m,index j=(1, 3, 5, 7, . . . , m-3, m-1) and j=(1, 3, 5, 7, . . . , m-4,m-2, m-1) for odd-numbered m, and the nodes of lines i and i+1 areconnected together pairwise with four additional fibers in the columndirection, where index i=(1, 3, 5, 7, . . . , n-3, n-1) is used foreven-numbered n, and i=(1, 3, 5, 7, . . . , n-4, n-2, n-1) is used forodd-numbered n. This offers the advantage that the abovementionedprotection paths for signals whose path used in normal operation hasbeen interrupted by an accident, can be switched for all light fluxes ofthe network in the optical range. The additional fibers added form anarrangement of topologies in "comb form," the spatially disjunctivealterative protection paths to the paths that run only within lines orcolumns of the network. The fact that these "comb forms" are arranged insuch fashion that the "comb arms" have the shortest possible lengthindicates that the ratio between the path length and Euclidean distancebetween two nodes of a line or column is minimal. Another advantageresults from the complete utilization of the capacities freed up by theprotection paths along the "comb back" of the protection paths and,through maximum utilization of the additional fibers with (m-1) and(n-1) light fluxes, defines various wavelengths for addressing (m-1) or(n-1) nodes of the same line or column. Time slots are assigned to thenetwork in a periodic sequence, within which slots the network isalternately switched to one of two possible signal paths. This offersthe advantage that for each of the signal paths of a network operated insuch fashion, an alternative signal path exists within every other timeslot that can be utilized optionally as a complete replacement only inthe case of damage, or it can be used continuously. When the latteralterative is chosen, only a halving of the transmission capacityutilized can be expected in spatially delimited accidents.

Two networks are operated in parallel with different signal pathselection possibilities, and have the advantage that, likewiseoptionally, a spatially disjunctive "mirror system" can be used as acomplete replacement in the event of an accident or a doubledtransmission capacity can be used that is "halved" once again in theevent of an accident.

The network can be expanded in such fashion that nodes of the networkare connectable by at least two additional optical fibers from nodesother than those of the network to at least one node. This has theadvantage that a communications capability, in other words abidirectional data transmission possibility, of the nodes in the networkwith the nodes of another network is achieved.

The network can be expanded by virtue of the wavelength multiplexer andwavelength demultiplexer in use being operable with a minimum of onewavelength more than is required for full intermeshing, with it beingpossible to provide additional optically transparent paths to achieve acommunications capability for the nodes in the network with nodes ofother networks of the same design, with these optical paths not havingtheir respective transmitting and receiving points at the marginal nodesof the network alone. If the number of optical transparent paths forlinking two networks is increased in this manner, the advantage isobtained that the number of transmitters and receivers on the partialpaths that divide the transmission capacity of these wavelength pathsand must be synchronized with one another, is reduced. In the event ofmaximum utilization of the transmission capacities, in the case of afull intermeshing of m×n nodes, with m=n, using only m wavelengthsdefined as different, the required condition is meet of increasing theaddressing space in order to forecast a "penetration or intermeshingdepth" of the transparent path that is greater than 1. "Penetrationdepth 1" is intended to mean that at least one of the peripheral nodesof the network can be reached. Penetration depth "N" is intended to meanreaching up to a minimum of one node of the N-th line or column,depending on the direction of penetration.

For all nodes (1, 1 to n, m) looking in both column and line directions,at least N·(N-1) connections are provided and the address of the line ofeach node is encoded into one of at least 2·N-1 wavelengths defined asdifferent, and each node can be addressed using one of at least 2·N-1wavelengths defined as different for the nodes of a line, where N is thelarger of the two numbers n and m. Firstly, this has the advantage thatthe number of nodes intermeshed with one another can be expanded asdesired. There is the additional advantage that a "penetration orintermeshing depth" of the optically transparent paths of N-1 columnsand N-1 lines is always provided in the expanded as well as theexpanding part of the network, and hence there is the further advantagethat all the partial networks of N×N nodes are fully intermeshed withone another. In addition, the utilization of the transmission capacityof the fibers by the nodes that utilize the paths to N·N-1 other nodesis maximized. In the boundary case of the intermeshing of an infinitenumber of nodes, all of the transmission capacities provided areutilized.

BRIEF DESCRIPTION OF THE DRAWINGS

Further details of the invention will follow from the description belowof special embodiments according to the drawings.

FIG. 1 is a telecommunications network according to the invention with atotal of nine nodes, in a schematically simplified block diagram;

FIG. 2 is an address table to explain the addressing of the nodes of thenetwork according to FIG. 1;

FIG. 3 shows the schematic diagram of a corner node of the networkaccording to FIG. 1, composed of wavelength demultiplexers, wavelengthmultiplexers, waveguides, transmitters, and receivers;

FIG. 4 shows the structure of the central node of the network accordingto FIG. 1 in a view similar to FIG. 3;

FIG. 5 shows one node of a network whose function is analogous to thenetwork in FIG. 1, in which addressing is performed by a combination ofwavelengths and time slots;

FIG. 6 shows a transport network according to the invention withmaximized utilization of the transmission capacity of the fibersemployed with m·n nodes in a schematically simplified block diagram;

FIG. 7 shows a transport network according to the invention withmaximized utilization of the transmission capacity of the fibers used,with 5×5, in other words a total of 25, nodes in a schematicallysimplified block diagram;

FIGS. 8a and 8b show an address table to explain the addressing of thenodes of the network according to FIG. 7;

FIG. 9 shows the structure of a node of the network according to FIG. 7composed of wavelength demultiplexers, wavelength multiplexers,waveguides, transmitters, and receivers;

FIGS. 10a to 10d show the "comb structures" of the network according toFIG. 7 that are required to generate paths that are spatiallydisjunctive from the lines and columns of the network, and

FIG. 11 shows the structure of one node of the expanded networkaccording to FIG. 10 in a view similar to FIG. 9;

FIG. 12 is a transport network according to the invention whose numberof nodes can be expanded to an infinite extent in the limiting casedespite maximized utilization of the transmission capacity of the fibersused, in a schematically simplified block diagram;

FIG. 13 is an address table to explain the addressing of the nodes ofthe network according to FIG. 12.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Using the network designated in FIG. 1 as a whole by 10, which is formedby a number of nodes 11 to 13, 21 to 23, and 31 to 33 and the datatransmission lines connecting them, through which lines the individualnodes 11 to 13, 21 to 23, and 31 to 33 together form a matrix, areconnected together along lines 14 to 16 and columns 24 to 26, a completemeshing of nodes 11 to 13, 21 to 23, and 31 to 33 with one another is tobe achieved in such fashion that every network node can "address" everyother node in the network at the same time, i.e. can send data to thelatter and at the same time every node can be "addressed" by every othernode, in other words, data can be received from any other node.

The term "data" will be understood hereinbelow to refer to digitalmodulated signals that are conducted as light fluxes through opticalfibers, with the objective information content of these data streamsbeing encoded into the modulation of the light fluxes, while the addressinformation is encoded in various wavelengths of these light fluxes orpartly in different wavelengths of these light fluxes and to anadditional degree in the time sequence of time slots at which theindividual nodes are ready to transmit and receive, or the addressinformation is encoded exclusively in the arrangement of time windows ortime slots at which the nodes are ready to transmit or receive.

In the case of the embodiment chosen for explanation, without limitationof its general nature, it is assumed that the network has a total ofnine nodes, arranged in a "square" 3×3 matrix, and that the addressinformation is encoded exclusively in the wavelengths of the lightfluxes that are digitally modulated to transmit the content information.

In the 3×3 matrix shown, nodes 11, 12, 13 and 21, 22, 23, or 31, 32, 33arranged in a line 14 to 16 are connected pairwise with one another bythree optical fibers 17 to 19. Similarly, nodes 11, 21, and 31 as wellas 12, 22, and 32 and 13, 23, and 33 arranged along columns 24 to 36 arelikewise connected together by three optical fibers 27 to 29.

In the general case that the number m of nodes is located along a lineand the number n is located along a column, the number of optical fibersrunning in the line direction that each connecting two nodes pairwisewith one another is m, and the optical fibers running in the columndirection is n, with these fiber bundles being combined into cables. Ascarriers for the data streams possible within network 10, n×m (in theembodiment shown, 9) light fluxes of the wavelength λ_(I), λ_(II), . . ., λ_(IX) defined as different are used. Since (n×m-1) nodes must beaddressable from each node, each node must also be capable oftransmitting and receiving eight light fluxes of the stated wavelengths.

In the general case that the number m of nodes is located along one lineand the number n along one column, n×m wavelengths defined as differentλ_(I), λ_(II), . . . , λ_(n)×m serve as carriers for the data streamspossible within network 10, or k wavelengths defined as different λ₁,λ_(II), . . . , λ_(n)×m and j different time slots S₁, S₂, . . . ,S_(j), which, combined into pairs, represent the addresses I=(λ_(I),S₁), II=(λ₁ S₂) , . . . , n×m=(λ₁, S_(j)) as carriers for the datastreams (whereby n×m must be ≦k×j or n×m time slots defined as differentS_(I), S_(II), . . . , S_(n)×m in which the nodes are respectively ableto transmit and receive.

To explain a suitable addressing method in which the addressing of theindividual nodes can be performed from any desired node, it should nowbe mentioned in addition to FIG. 2 in which, in an arrangement ofcolumns 24 to 26 analogous to FIG. 1, corresponding address fields 24'to 26' are shown and within which one of the wavelengths at which therespective nodes can emit an information light flux is represented by anumber field 36. These number fields in terms of their matrix-typearrangement correspond to the matrix arrangement of nodes 11 to 13, 21to 23, and 31 to 33, with a transmitting node being designated by fields37 "crossed" in each case, and the "target" node that is to be addressedis designated by the arrangement within matrix 36, 37. From the diagramin FIG. 2 it therefore follows that node 12 is addressed by node 11 atwavelength II while node 13 is addressed by node 11 at wavelength III.

The nodes 21 to 23 of network 10 according to FIG. 1 are addressed inthis sequence from node 11 by wavelength IV and V as well as VI. Nodes31 to 33 of network 10 according to FIG. 1 can be addressed by nodes 11in this network 10, in the sequence given, at wavelengths VII VIII, andIX.

The addressing of the individual nodes via the total of nine lightfluxes defines various wavelengths I to IX, firstly by selection ofoptical fibers 17 to 19 by which columns 24 to 26 are selected as aresult, and also by their addressing within one of columns 24 to 26 bythe wavelength of the respective information light fluxes.

Optical fibers 17 run from each of the nodes from columns 25 and 26 ofnetwork 10 according to FIG. 1 to column 24 of network 10. Opticalfibers 18 conduct the light fluxes of the nodes in columns 24 and 26 tocolumn 25 of network 10 and the optical fibers 19 conduct the lightfluxes of nodes 11, 12 and 21, 22 as well as 31 and 32 of columns 24 and25 to column 26 of network 10.

Optical fibers 27 conduct the data streams from nodes 11, 12, and 13 inlines 14 in network 10 according to FIG. 1 to nodes 21 to 23 in line 15and nodes 31 to 33 in line 16. Optical fibers 28 conduct the lightfluxes of the nodes in line 15 to the nodes of lines 14 and 16 andoptical fibers 29 conduct the light fluxes of the nodes in line 16 tonodes 11 to 13 and 21 to 23 in lines 14 and 15. For example, if node 32in this network 10 is to be addressed by node 23 of network 10 accordingto FIG. 1, this addressing is accomplished by virtue of the fact thatvia the "middle" optical fiber 18, that links node 23 with "central"node 22 of the network, a light flux with wavelength IX is transmittedthat is conducted via the additional "middle" optical fiber 28, linkingcentral nodes 22 with node 32 located below as shown in FIG. 1, to thisnode 32.

Similarly, according to the address table in FIG. 2, the other nodes canbe addressed by each of nodes 11 to 13, 21 to 23, and 31 to 33.

In the general case in which m nodes are provided along a line and nnodes are provided along a column, the number of optical fibers (m-k)supplied unidirectionally in the positive line direction by the k-thnode of a line, according to the (m-k) columns with n nodes each, whichare addressable by k nodes of the line, and the number of optical fibers(k-1) supplied unidirectionally in the negative line direction with datastreams, according to the (k-1) columns with n nodes each. The number ofoptical fibers traversed "upward" by data streams in the positive columndirection unidirectionally from the j-th node of a column is (j-1)according to the (j-1) nodes which are addressable by (n-j) lines with mnodes each, and the number of optical fibers traversed "downward" bydata streams in the negative column direction unidirectionally from thej-th node of a column is (n-j) according to the (n-j) nodes, that areaddressed by j lines with m nodes each.

As another addressing example, the addressing of node 21 of network 10according to FIG. 1 from node 12 is explained, which according to theaddress table in FIG. 2 takes place through wavelength VI, as indicatedby number field 36₂₁ of address field 25'. The light flux of "address"wavelength VI travels through optical fiber 17 connecting node 12 withnode 11 to node 11 and is looped through the latter, so to speak, to itsoutput lead 27, which within node 21 reaches a receiver 49 of node 21,which is addressed and controlled thereby.

"Corner nodes" 11, through which the address light flux is conducted tonode 21 in the example given, has, in greater detail, the design shownin FIG. 3, to which reference will now be made:

Node 11, in the arrangement shown in detail in FIG. 3, has threewavelength demultiplexers 39 and 41 as well as 42 and three wavelengthmultiplexers 43 and 44 as well as 46.

The wavelength demultiplexers constitute receiving elements that dividea light flux conducted to them, containing partial light fluxescorresponding to one or more of wavelengths I to IX, into the individuallight flux components of the various wavelengths. Accordingly, each ofthese wavelength demultiplexers 39 and 41 as well as 42 has an opticalinput 47, to which optical fibers 17 and 28 as well as 29 that lead tonode 11 are connected, and nine outputs 48 at which the partial lightfluxes associated with the various wavelengths I to IX emerge spatiallyseparated from one another in an orderly sequence, to the extent thatthey are contained in the total light flux admitted through input 47.Depending on the function of these partial light fluxes, they are eitherconducted to a receiver 49 that promotes their conversion intoelectrical signals that are supplied for further electronic processingor to the input side of one of the wavelength multiplexers 46 or 43 or44 which form the output members of the respective nodes 11 to 13, 21 to23, and 31 to 33 and have a number of coupling inputs 51 thatcorresponds to the number of wavelengths I to IX which are linked eitherwith one of outputs 48 of one of the wavelength demultiplexers in orderfor example simply to further conduct a light flux through node 11, orare connected to a transmitter 55 through which information signals canbe coupled into the respective multiplexers 43 or 44 or 46 whichrepresent digital data that are intended to be conducted further by oneof the nodes to the node being addressed, and are supposed to beaccessible for further processing through the latter.

In corner node 11 shown in FIG. 3, its addressing by node 12 takes placevia optical light conducting fiber 28 connected to optical input 47 ofwavelength demultiplexer 39, whose light flux component with wavelengthVI that is utilized to address node 14 travels via internal waveguide 52to coupling input 51, likewise associated with wavelength VI ofwavelength multiplexer 46 shown at the bottom left in FIG. 3, and fromwhose optical output 53 it is coupled into optical fiber 34 that leadsto node 21. From "input" demultiplexer 39, a second waveguide 54provided for addressing a node leads to "output" multiplexer 46 to whichfirst waveguide 52 is also connected, with this second waveguide beingprovided for transmission of light flux with wavelength V by means ofwhich the same node 21 is addressable from the "addressing", "right"corner node 13.

The two additional waveguides 56 and 57, that connect the inputwavelength demultiplexer 39 with the output wavelength multiplexer 46are provided firstly for the addressing of the corner node 31 shown inthe bottom left part of FIG. 1 by the upper right node 13 by means ofwavelength VIII and also for addressing corner node 31 by the node 12located between the two corner nodes 11 and 13 of network 10 by means ofwavelength IX.

The two wavelength multiplexers 43 and 44 located "below" inputdemultiplexer 39 are provided firstly for delivering signals foraddressing nodes 12, 22 and 32 and 13, 23, and 33 arranged in columns 25and 26, with the nodes located in column 25 (FIG. 1) being addressableby wavelength multiplexer 43, with the addressing of node 12 takingplace by means of wavelength II, the addressing of node 22 by means ofwavelength V, and the addressing of node 32 by means of wavelength VIII,using optical fiber is in each case, while nodes 13, 23, and 33 locatedin column 26 are addressable by means of wavelength multiplexer 44, withthe addressing of corner node 13 being performed by means of wavelengthIII, the addressing of the middle node 23 by means of wavelength VI, andthe addressing of the lower right corner node 33 in FIG. 1 by means ofwavelength of through optical fiber 19 in each case.

The addressing light fluxes required in this regard are generated bytransmitters 55, which are connected to the corresponding inputs 51 ofmultiplexers 43 and 44 associated with the individual wavelengths of thetransmission light fluxes. Transmitter 55 with this function ofgenerating light fluxes which address individual nodes through theirwavelengths, are also provided in the "output" multiplexer shown in thebottom left part of FIG. 3, which are used to address nodes 21 and 31located in the left column 24 of matrix network 10.

Receivers 49 with the function of transforming the data streams encodedin the light fluxes into electrical signal leads are also provided forthe wavelengths of demultiplexers 41 and 42, which are connected tooutputs 48 of wavelengths I to III in order for lines 15 and 16 ofnetwork 10 according to FIG. 1 to be addressed by nodes 21 to 23 and 31to 33.

In addition, the central cross node 22 shown in FIG. 4 of network 10 isconstructed in a manner analogous to the structure of corner node 11described with reference to FIG. 3, from wavelength demultiplexers 61,62, 63, 64, and 65, as well as 66, on the one hand and wavelengthmultiplexers 67, 68, 69, 71, and 72 as well as 73 on the other, to whoseinputs 47 and or optical outputs 53 one of optical fibers 17 to 19 or 27to 29 is connected, through which addressing and information signals aresent to node 22 or are sent out from the latter in the "line direction"or "column direction".

The "internal" waveguides that transmit information signals "in the linedirection" are labeled 74, 76, 77 and 78, 79, 81; functionallycorresponding light waveguides which transmit the addressing andinformation signals "in the column direction" through the central nodesare labeled 82, 83, 94 as well as 85, 86, 87, while the light waveguidesthrough which input light fluxes that are conducted through the "middle"optical fibers 29 to the wavelength demultiplexers 62 and 65 aredeflected in the direction of second column 25 of matrix network 10, arelabeled 88 and 89 as well as 91 and 92.

Depending on the number of light fluxes that are conducted by nodes 11to 13, 21 and 23, and 31 to 33 to central node 22, said node is providedwith a total of eight receivers 49 and central node 22, corresponding tothe number of nodes addressable from central node 22, is also providedwith eight transmitters 55 each of which transmits on one of the totalof eight wavelengths I to III and V to IX.

In the case of the embodiment shown in FIG. 5, without limitation of itsgeneral nature, it is assumed once again that the network has a total of9 nodes arranged in a "quadratic" 3×3 matrix and that the addressinformation is encoded both into the wavelengths of the light fluxes andinto the time slots in which the transmitters and receivers are preparedto send and receive. For the explanation, see Table 1.

                  TABLE 1                                                         ______________________________________                                        101        102          103                                                   Address    WDM Gridconnect                                                                            WDM/TDM Gridconnect                                   ______________________________________                                        I          λ.sub.1                                                                             λ.sub.1,S.sub.1                                II         λ.sub.2                                                                             λ.sub.2,S.sub.1                                III        λ.sub.3                                                                             λ.sub.3,S.sub.1 \                    IV         λ.sub.4                                                                             λ.sub.1,S.sub.2 /                                                                 104                                        V          λ.sub.5                                                                             λ.sub.2,S.sub.2 /                              VI         λ.sub.6                                                                             λ.sub.3,S.sub.2                                VII        λ.sub.7                                                                             λ.sub.1,S.sub.3                                VIII       λ.sub.8                                                                             λ.sub.2,S.sub.3                                IX         λ.sub.9                                                                             λ.sub.3,S.sub.3                                ______________________________________                                    

In the first column 101 of this table, addresses I, II, . . . , IX arelisted in the sequence to which the various wavelengths λ₁, λ₂, . . . ,λ₉ listed in column 102 or the wavelength-time slot pairs (λ₁,S₁),(λ₂,S₁), (λ₃,S₁), (λ₁,S₂), . . . , (λ₃,S₃) 104 of wavelengths λ₁, λ₂,and λ₃ listed in column 103 and the time slots S₁, S₂, and S₃ areassigned. With this allocation of wavelength-time slot pairs toaddresses by analogy with the address table in FIG. 2, address fields24' to 26' in FIG. 2 can be used to describe the addressing method ofthe second embodiment. For this purpose, reference is now made to FIG. 5that shows second node 12 of first line 14 of network 10 according toFIG. 1 in greater detail:

Wavelength demultiplexers 106 to 108, and 109, 111, and 112 as receivingelements decompose the light fluxes that are fed into their opticalinputs 113 through optical fibers 17, 18, 29, 28, and 19 into partiallight fluxes with wavelengths λ₁, λ₂, and λ₃ that emerge again atoptical outputs 114. Wavelength multiplexers 116 to 118 guide thepartial light fluxes with wavelengths λ₁, λ₂, and λ₃ fed in at opticalinputs 119 to optical outputs 121 at which optical fibers 19, 27 and 17are connected together once more to a single optical waveguide. Then, asalready described with reference to the first embodiment, the datastreams emerging from node 13 are looped through to column 24 of network10 according to FIG. 1 and the output data streams of node 11 are fed tocolumn 26 of network 10 according to FIG. 1, with a light waveguide 122connecting optical output 114, associated with wavelength λ₂, ofwavelength demultiplexer 106 with optical input 119, associated withwavelength λ₂ of wavelength multiplexer 118, and another light waveguide123 connects optical output 114, associated with wavelength λ₃, ofwavelength demultiplexer 111 with optical input 119, associated withwavelength λ₃, of wavelength multiplexer 116. In addition, opticalwaveguide 124 and 126 connect optical outputs 114 of wavelengthdemultiplexers 107 and 112 with optical inputs 119 of wavelengthmultiplexers associated with wavelengths λ₂ and λ₃. Optical powerdividers 127 allow time demultiplex receivers 128 to receive the datastreams transmitted within time slot S₁ that are used according to theaddress table in FIG. 2 and the allocation according to Table 1 foraddressing node 12. When the data streams are transmitted by nodes 21 to23 and 31 to 33 to the nodes of column 25 of network 10 according toFIG. 1 at node 12, time demultiplex receivers 128 can directly tap thepartial light fluxes at optical outputs 114 of wavelength demultiplexers108 and 109 and use them to detect the data streams within time slot S₁.

Time multiplex transmitters 129 each transmit on one of wavelengths λ₁,λ₂, and λ₃ a light flux with three partial data streams that can beaccessed within time slots S₁, S₂ and S₃. These light fluxes are guidedto optical inputs 119 of wavelength multiplexer 116, 117, and 118, eachof which is allocated to one of wavelengths λ₁, λ₂, and λ₃ in accordancewith address column 24 or 25 or 26 of network 10 according to FIG. 1. Alight flux conducted for example from node 13 of network 10 according toFIG. 1 to central node 22 is encoded on fiber 18, wavelength λ₃, andtime slot S₂ according to address field 27' and number field 36₂₂ inFIG. 2 and the allocation of column 103 of Table 1 and is received atnode 12 of network 10 according to FIG. 1 at optical input 113 ofwavelength demultiplexer 107 according to FIG. 5. The light flux emergesat optical output 114 of wavelength demultiplexer 107 associated withwavelength λ₃ and is received by wave guide 126, from which opticalpower is decoupled at power divider 127 and fed to time demultiplexerreceiver 128 in order to be guided at optical input 119 of wavelengthmultiplexer 117, associated with wavelength λ₃ to optical fiber 27through optical output 121.

The light flux is fed to the determining node 22 over this optical fiber27. The data stream which is fed from node 13 of network 10 according toFIG. 1 to node 12 is encoded by the choice of fiber 18, wavelength λ₃,and time slot S₁ according to address field 26' and number field 36₁₂ inFIG. 2, and the allocation of column 103 in Table 1 and is received atnode 12 of network 10 according to FIG. 1 at optical input 113 ofwavelength demultiplexer 107 according to FIG. 5. Similarly, at thelight flux associated with wavelength λ₃ at optical output 114 ofwavelength demultiplexer 107, the emerging light flux is received bywaveguide 126, decoupled from the optical power at power divider 127 anddelivered to time demultiplex receiver 128. In the electronic range, thelatter can separate the partial data stream transmitted within time slotS₁ from the partial data streams transmitted within time slots S₂ and S₃and thus result in a reuse. Similarly in this fashion, each of nodes 11to 13, 21 to 23, and 31 to 33 of network 10 according to FIG. 1 canaddress and respond to every other node 11 to 13, 21 to 23, and 31 to 33and can also receive data from each of these nodes 11 to 13, 21 to 23,and 31 to 33.

Similarly to the method described in the first embodiment, addressingwith n×m time slots defined as different can take place, but for thistime multiplexing and time demultiplexing in the optical range arerequired that assume synchronization of the light fluxes from oneanother. The wavelength multiplexers 43, 44, 46 according to FIG. 3 and68, 69, 72, and 73 according to FIG. 4 would then be replaced by opticaltime multiplexers and the wavelength demultiplexers 39, 42, 41 accordingto FIG. 3 and 61, 62, 63, 64, 65, and 66 according to FIG. 4 would bereplaced by optical time demultiplexers.

For the additional embodiment shown in FIGS. 6 and 7 of a network 10with maximized utilization of the transmission capacity provided byglass fiber links, it is also assumed that the network designated inFIG. 6 as a whole by 10, generally comprises n·m nodes. Lines 14, 15 to601 and 602(n) of network 10 are marked with an i and columns 24, 25 to610 and 611(m) of network 10 are marked with a j, where i=(1, 2, . . . ,n-1, n) and j=(1, 2, . . . , m-1, m). Nodes (1,1 to n,m) are given thecorresponding index combination i,j corresponding to their line i andtheir column j.

From each node (I,1) of column 24 (m-1) optical glass fibers run in the"mathematically" positive line direction (from "left" to "right") toadjacent nodes (i,2). From each node (i,m) in column 611, (m-1) opticalglass fibers run in the mathematically negative line direction (from"right" to "left") to adjacent nodes (i,(m-1)). From each node (1,2 to1,(m-1); 2,2 to 2,(m-1); . . . ; n,2 to n,(m-1)) of columns 25 to 610(m-j)·j optical glass fiber connections are drawn in the mathematicallypositive line direction to the adjacent nodes (i,(j+1)) of line i and(m-j+1)·(j-1) glass fiber connections are drawn in the mathematicallynegative line direction to adjacent nodes (i,(j-1)) of line i. Thus,between nodes (1,1 to n,m) there is a pairwise connection that issymmetrical in the propagation direction of the light fluxes of2·(m-j)·j fibers between nodes (i,j) and (i,(j+1)) of line i. From eachnode (1,j) of line 14, (n-1) optical glass fibers extend in themathematically positive column direction (from "top" to "bottom") to theadjacent nodes (2,j). From each node (n,j) of line 602, (n-1) opticalglass fibers extend in the mathematically negative column direction(from "bottom" to "top") to the adjacent nodes ((n-1)j). From each node(2,1 ; . . . ; 2,m; . . . ; (n-1),1; . . . ;(n-1),m) of lines 15 to 601(n-i)·i optical glass fiber connections run in the mathematicallypositive column direction to the adjacent nodes ((i+1)j) of column j and(n-i+1) (i-1) glass fiber connections run in the mathematically negativecolumn direction to the adjacent noes ((i-1),j) of column j. Thus,between nodes (1,1 to n,m) there is a pairwise connection that issymmetrical in terms of the propagation direction of the light fluxes of2·(n-i)·i fibers between nodes (i,j) and ((i+1)j) of column j.

To explain the addressing method suitable for maximizing the utilizationof the transmission bandwidth of the fibers, reference will now be madeto FIG. 7 and Table 801 in FIGS. 8a and 8b. In the network 10 shown inFIG. 7, without limitation of generality, 25 nodes (711-715, 721-725,731-735, 741-745, 751-755) are provided arranged in a "quadratic" 5×5matrix. These nodes are connected by the data transmission lines (glassfibers) (760-779) and (780-799) pairwise along lines 14, 15, 16, 717,and 718 and along columns 24, 25, 26, 727, and 728 into a latticenetwork.

In FIGS. 8a and 8b, an address table 801 is shown in two differentpositions of a "read frame" 802 that correspond to two different"addressing tasks" with FIGS. 8a and 8b showing the case in which thewavelength FIGS. I to V located inside the frame window indicate thewavelengths at which all other nodes in network 10 according to FIG. 7can be addressed from node 1,1, while the position of read frame 802 inFIG. 8b corresponds to the problem of being able to read the wavelengthsby which all other nodes of the network are addressable from nodes 3,4,naturally in combination with the selected fiber in each case throughwhich this node is connectable with the other nodes of this network.

The address table is constructed so that the transmitting node isrepresented by central field 803 in the circle and, depending on theposition of frame 802, its indexing within the network according to FIG.7 of the transmitting node is selected. Its indexing is sought, so tospeak, in the "matrix arrangement" of read frame 802 and the read frameis positioned so that the node corresponding to the desired indexingcoincides with field 803 of address table 801. It is then possible toread immediately within read frame 802 the wavelengths at which theother nodes of the network can be addressed from the transmitting node.

Accordingly, nodes 721, 731, 741, and 751 in column 24 in FIG. 7 areaddressed by node 711 with wavelengths II, III, IV, and V. Nodes 712,722, 732, 742, and 752 in column 25, nodes 713, 723, 733, 743, and 753in column 26, nodes 714, 724, 734, 744, and 754 in column 727, and nodes715, 725, 735, 745, and 755 in column 728 are addressed by nodes 711 atwavelengths 1, II, III, IV, and V.

Fibers 760 to 779 of lines 14, 15, 16, 717, and 718, which connectcolumns 24, 25, 26, 727, and 728 pairwise with one another, aredesignated in accordance with the original column and the target columnof the transported data streams conducted by the fiber. Similarly,fibers 780 to 799 in column 24, 25, 26, 727, and 728 which connect lines14, 15, 16, 717, and 718 pairwise with one another are designated inaccordance with the original line and target line of the data streamstransported by the fiber. The fibers of lines 14, 15, 16, 717, 718accordingly are referred to as follows: "from column j_(transmitter) tocolumn j_(receiver) " and the fibers of columns 24, 25, 26, 727, and 728are referred to as follows: "from line i_(transmitter) to linei_(receiver)."

The designations of all the fibers 760 to 799 in network 10 are listedin Table 2. It is evident from columns 201 and 202 in Table 2 thatfibers 760 that lead the data streams coming from nodes 711, 721, 731,641, and 751 of column 24 to nodes 715, 725, 735, 745, and 755 of column728 according to FIG. 7, are referred to as those fibers which carrydata streams "from column one (24) to column five (728)" (C1→C5), andthose fibers are referred to as fibers 762 that conduct the light fluxescoming from nodes 711, 721, 731, 741, and 751 in column 24 to nodes 713,723, 733, 743, and 753 in column 26 according to FIG. 7, in other words,as the fibers that carry data streams "from column one (24) to columnthree (26)" (C1→C3).

                  TABLE 2                                                         ______________________________________                                        760   C1→C5                                                                          770    C5→C1                                                                        780   R1→R5                                                                        790  R5→R1                      761   C1→C4                                                                          771    C5→C2                                                                        781   R1→R4                                                                        791  R5→R2                      762   C1→C3                                                                          772    C5→C3                                                                        782   R1→R3                                                                        792  R5→R3                      763   C1→C2                                                                          773    C5→C4                                                                        783   R1→R2                                                                        793  R5→R4                      764   C2→C5                                                                          774    C4→C1                                                                        784   R2→R5                                                                        794  R4→R1                      765   C2→C4                                                                          775    C4→C2                                                                        785   R2→R4                                                                        795  R4→R2                      766   C2→C3                                                                          776    C4→C3                                                                        786   R2→R3                                                                        796  R4→R3                      767   C3→C5                                                                          777    C3→C1                                                                        787   R3→R5                                                                        797  R3→R1                      768   C3→C4                                                                          778    C3→C2                                                                        788   R3→R4                                                                        798  R3→R2                      769   C4→C5                                                                          779    C2→C1                                                                        789   R4→R5                                                                        799  R2→R1                      ______________________________________                                    

From columns 205 and 206 of Table 2 we can see that fibers 787 thatconduct the light fluxes coming from nodes 731, 732, 733, 734, and 735in line 16 to nodes 751, 752, 753, 754, and 755 of line 718 according toFIG. 7 are referred to as those fibers that carry data streams "fromline three (16) to line five (718)" (R3→R5).

The addressing of the individual nodes through the total of five lightfluxes with wavelengths I to V defined as different, is accomplished byselecting the optical fibers 760 to 779 by which columns 24, 25, 26,727, and 728 are selected as a result, and also by their addressingwithin one of columns 24, 25, 26, 727, and 728 by the wavelength of thecorresponding information light fluxes.

The choice of fibers is made in accordance with Table 2 and the choiceof wavelengths is made using address table 801 as shown in FIGS. 8a and8b.

For example, if node 742 in this network 10 is to be addressed by node711 in network 10 according to FIG. 7, its addressing takes place asfollows: a light flux with wavelength V (FIG. 8a, number field 842) istransmitted through optical fiber 760, connecting node 711 (1,1) withnode 712 of the network, said flux being conducted by means ofadditional fibers 781 via nodes 722 and 732 to this node 742. As anotheraddressing example, the addressing of node 721 of network 10 from node734 is explained according to FIG. 7, which takes place according to theaddress table in FIG. 8b at wavelength II, as indicated by the numberfield 822 of address field 801. The light flux of "address" wavelengthII travels through optical fiber 774 linking nodes 733 and 732 with node731 to reach node 731 and is looped through the latter, so to speak, toits output lead 798 which, within node 721, reaches a receiver 49 ofthis node 721, which is addressed and controlled thereby.

By selecting the five wavelengths I, II, III, IV, and V defined asdifferent for addressing within one of lines 14, 15, 16, 717, and 718 ofnetwork 10, it turns out that none of wavelengths I, II, III, IV, and Vis used twice within one of fibers 780 to 799. By cyclic reversal of thefive wavelengths I, II, III, IV, and V defined as different in lines814, 815, 816, 817, and 818 of address table 801 that are analogous tolines 14, 15, 16, 717, and 718 of network 10 (number fields 811 to 815,821 to 825, 831 to 835, 841 to 845, and 851 to 855) it turns out thatnone of the wavelengths is used twice within one of fibers 760 to 799.In the general case that m nodes are arranged along a line and n nodesare arranged along a column, the number of wavelengths to be selectedthat are defined as different corresponds to the larger of the twonumbers.

Nodes (711-715, 721-725, 731-735, 741-745, 751-755) can have a structureanalogous to that described in FIGS. 3 and 4, whereby each fiber 760 to799 that leads to a node at input 47 of a wavelength demultiplexer thatspatially separates the five wavelengths of the light flux defined asdifferent and steers the light signals to waveguides at its outputs 48.These waveguides in turn lead either to a receiver 49 or to one ofinputs 51 of the wavelength multiplexers that bring together the lightfluxes of the wavelengths defined as different to a common output 53.The signals from transmitters 55 on waveguides are likewise brought tothese inputs 51. Each of outputs 53 feeds the light flux resulting froma superimposition of the light fluxes of the five wavelengths I, II,III, IV, and V defined as different into one of fibers 760 to 799extending from nodes (711-715, 721-725, 731-735, 741-745, 751-755).Depending on the number of light fluxes that can be transported fromnodes (711-715, 721-725, 731-735, 741-745, 751-755) to any other node,each of these nodes is provided with a total of twenty-four receivers49, each of which can receive on one of the total of five wavelengths Ito V, and with twenty-four transmitters 55 that can transmit on one ofthe total of five wavelengths I to V. In the general case that m nodesare located along a line and n are located on a column, the number ofreceivers 49 and transmitters 55 in each node is (m·n-1), with each ofthe m-1 wavelengths defined as different that are used for addressingwithin a line being utilized n times. The first of the m wavelengths Idefined as different is utilized according to address table 801 in FIGS.8a and 8b only (n-1) times.

To create network 10 explained in FIGS. 6 and 7, as well as 8a and 8b,the design of its nodes is provided that is explained in FIG. 9 and isuniform for all nodes in the network.

Those fibers that carry light fluxes that go from one line or one columnof network 10 to one line or one column of network 10, neither of whichcorresponds to that of node (i,j) are simply conducted through at node(i,j). In the line direction, there are 2·(m-j)·(j-1) fibers and in thecolumn direction, 2·(n-i)·(i-1) optical glass fibers. The remaining(m-1) fibers that transmit data coming from nodes in line i to column jand the (n-1) fibers that transport the light fluxes from lines (1, 2, .. . , i-1, i+1, . . . ,n) to nodes (i,j) are conducted to inputs 47 ofwavelength demultiplexer 901 according to FIG. 9. Wavelengthdemultiplexers 901 separate the light fluxes of wavelengths I, II, II,IV and V defined as different spatially and conduct these light fluxesto outputs 48. At these outputs 48, the light fluxes are picked upeither by receivers 49 or waveguides 903. Receivers 49 convert theoptical signal into an electrical signal and conduct it for further use.Waveguides 903 conduct the light fluxes corresponding to the targetnodes associated with the data to inputs 51 of wavelength multiplexers902 according to FIG. 9 that bring together the light fluxes ofwavelengths I, II, III, IV, and V defined as different to a commonoutput 53. Each of these outputs 53 of wavelength multiplexer 902 feedsthe light flux resulting from the superimposition of the light fluxes ofthe five wavelengths I, II, III, IV, and V defined as different to oneof the glass fibers that lead to lines (1,2, . . . , i-1, i+1, . . . ,n-1, n). (M-1) transmitters 55 of node (i,j) of network 10, each ofwhich generates a light flux for data transmission to one of the (M-1)other nodes of the network are likewise connected to inputs 51 ofwavelength demultiplexers 902 of node (i,j). The transmitted lightfluxes then reach, likewise through outputs 53 of wavelengthdemultiplexer 902, the (m-1) fibers that run from nodes (i,j) to the(m-1) columns (1,2, . . . , j-1, j+1, . . . , m-1, m) of network 10.

In linking outputs 41 of wavelength demultiplexer 901 by means of waveguide 903 to inputs 15 of wave multiplexer 902 according to FIG. 9, acyclic reversal is performed between wavelength demultiplexers 901 andwavelength multiplexers 902 for each of the five wavelengths I, II, III,IV, and V. This results in the function of a "WDM-Crossconnects."

The use of this structure according to FIG. 9 is provided for all nodes(1,1 to m,n) of network 10 and must be performed separately for eachnode only during the occupation of inputs 47 of wavelength demultiplexer901 and outputs 53 of wavelength multiplexer 902.

For example, if the structure of FIG. 9 constitutes nodes 712 (1,2) ofnetwork 10, the names of the fibers at inputs 47 read as follows from"top" to "bottom": (C1→C2), (C3→C2), (C4→C2), (C5→C2), (R2→R1), (R3→R1),(R4→R1), (R5→R1) and the fibers at output 53 read as follows in thissequence from "top" to "bottom": (R1→R2), (R1→R3), (R1→R4), (R1→R5),(C2→C1), (C2→C3), (C2→C4), (C2→C5).

For example, if the structure in FIG. 9 constitutes nodes 755 (5,5) ofnetwork 10, the fibers at inputs 47 read as follows in this sequencefrom "top" to "bottom": (C4→C5), (C1→C5), (C2→C5), (C5→C5), (R1→R5),(R2→R5), (R3→R5), (R4→R5) and the fibers at outputs 53 read as followsin this sequence from "top" to "bottom": (R5→R1), (R5→R2), (R5→R3),(R5→R4), (C5→C1), (C5→C2), (C5→C3), (C5→C4).

In the general case where network 10 has m columns and n lines, andwithout limitation of generality, m is made ≧n, for each node 2·(m-1)wavelength demultiplexer 901 is required with m outputs 48 and 2·(m-1)wavelength multiplexer 902 with m inputs 51.

To explain the special expansion of network 10, as described withreference to FIGS. 6 to 9, reference will now be made to FIGS. 10a to10b and 11. The nodes shown in FIGS. 10a, 10b, 10c, and 10d (911-915,921-925, 931-935, 941-945, 951-955) correspond to nodes (711-715,721-725, 731-735, 741-745, 751-755) of FIG. 7 and are connected pairwisewith one another by fibers 960 to 965 and 970 to 975. FIGS. 10a, 10b,10c, and 10d constitute basic segments that make it possible tosupplement a network 10 according to FIG. 6 that comprises m·n nodes inthe general case. In the case when m and n are even numbers, only m·n/4segments according to FIG. 10a are used in addition. In the case where mis an even number but n is an odd number, m·(n-3)/4 segments are usedaccording to FIG. 10a and m/2 segments are used according to FIG. 10c.In the case where m is an odd number but n is an even number, n·(m-3)/4segments are used according to FIG. 10a and n/2 segments are usedaccording to FIG. 10b. In the case where m and n are odd numbers,(m-3)·(n-3)/4 segments are used according to FIG. 10a and (n-3)/2segments are used according to FIG. 10b and (m-3)/2 segments are usedaccording to FIG. 10c as well as one segment according to FIG. 10d forexpansion.

The expansion of network 10 takes place in the form of "comb structures"that permit a spatially disjunctive selection of an alternativepropagation path between two nodes of a line i or a column j. From nodes911, 921, 931, 941, and 951 for example, as shown in FIGS. 10a or 10c,by means of fibers 960, those light fluxes that are guided in network 10as shown in FIG. 7 along column 24 can be supplied, so to speak, to the"teeth" of the comb structure in column 25 that forms the "back" of thecomb structure. Since the light fluxes between nodes 912, 922, 932, 942,and 952 must also be "rerouted" from column 25, the transmissioncapacity that has become available for transmitting the data for nodesin column 24 with one another along the "back" of the comb structure isused. Fibers 963 again carry light fluxes "from column 24 to column 24"along the "teeth" of the comb structure back to column 24. The same"comb structure" is utilized symmetrically by means of fibers 961 and962 to "reroute" the data streams from column 25 through column 24. Theprovision of the "comb structures" required for expansion for the caseof an odd number of columns is shown in FIGS. 10b and 10d, with column26 representing the "back" of a comb, whose "teeth" are formed by fibers964 and 965, which are connected with column 728. Column 727 conductsthe rerouted data streams that are guided in network 10 according toFIG. 7 along column 26 and are conducted by means of fibers 961 and 962of column 727. Similarly, an expansion for "rerouting" the light fluxeswithin lines 14, 15, 16, 717, and 718 is accomplished similarly byfibers 970 to 975.

To explain the structure for all the nodes, which is also uniform forthe expanded configuration of network 10, FIG. 11 shows the arrangementanalogous to FIG. 9, expanded by four additional wavelengthdemultiplexers 901 and four additional wavelength multiplexers 902, towhich are connected fibers 960 to 963, and fibers 970 to 973 (nodesaccording to FIG. 10a) or fibers 961, 962, 964, and 965 and fibers 970to 973 (nodes according to FIG. 10b) or fibers 960 to 963 and fibers971, 972, 974, and 975 (nodes according to FIG. 10c) or fibers 961, 962,964, and 965 and fibers 961, 962, 964, and 965 (nodes according to FIG.10d).

Starting with a network 10 with maximum utilization of the transmissioncapacity provided by the glass fiber connections, as shown in FIGS. 6and 7, a problem of expandability can result, namely that no fibers andno transmission wavelengths are any longer available as addressingpossibilities, with which nodes of network 10 would be addressable bythe additional nodes by which network 10 was expanded, or would beaddressable by the nodes of network 10 from the nodes by which network10 was supposed to be expanded. This is particularly the case when thenumber of columns m and the number of lines n and hence the number ofwavelengths used that are defined as different are identical and thus nosingle "free" address is any longer available in the address spacecovered. In this case, in other words when the supply of unused elementsof the address space is completely exhausted, an expansion of thenetwork is only possible when the transmission capacity provided by theglass fiber connections is not itself completely exhausted, in otherwords, the transmission bandwidth prepared for one or more of the signalpaths is not yet completely utilized. This use of the capacity of one ofthe signal paths is determined exclusively by the choice of thetransmission method, and in digital systems by the data transmissionrate. The selection of the data transmission rate and the transmissionmethod can be used in the designs of network 10 in which only theutilized wavelength and the utilized fiber are used for addressing, inother words, the signal path is a so-called "transparent" wavelengthpath, "bilaterally", in other words, separately for each individualtransmitter-receiver pair. The division of a transmission capacity ofsuch a wavelength path into various signal paths in order to permitaccess to the network from "outside" is only possible with an interfacethat uses either a frequency and/or a time and/or a code multiple accessmethod and for this reason is provided both on the transmitter side andin the receiver on the wavelength path. If the access method works todivide the transmission capacity of the wavelength path in theelectrical area, optoelectronic E/O, O/E converters are required foroperation. If an expansion of the network is accomplished by such anincrease in the addressing space, signal paths can consist of aplurality of partial paths that can be linked together only by means ofthe interfaces described. However, for these signal paths, theadvantages of a "transparency" of the wavelength paths, namely on atransparent path, only the transmitter and receiver are chosen to matchone another and must be synchronized with one another, i.e. noadditional transmitting or carrying components along the path dependupon the choice of the transmission method and a data transmission rate,can no longer be used or can be used only partially. An expansion of thenetwork is therefore advantageously provided in such fashion that thenumber of transparent wavelength paths from the nodes by which thenetwork is expanded to the nodes of network 10 along which the dataflows can be transported independently of one another, is made as largeas possible. In the best case, the nodes by which the network isexpanded fit completely into the functional transparent completeintermeshing of the network. A network 10 of the type described can beexpanded, in other words meshed with a network or partial network withthe same theoretical structure by transparent signal paths, in whicheither only the marginal or access nodes of the networks form thebeginning and end points of the transparent paths, or a certain"penetration or intermeshing depth" is provided. A transparentintermeshing of two networks with one another in such fashion that onlythe degree of the marginal or access nodes, i.e. the number of fibercables that are connected with a node, depends on the coupling of thenetworks, and a number of transparent wavelength paths is provided thatis larger than the number of connections between these access nodes, hasas necessary conditions that the addressing space of the networks is notfully utilized by the full intermeshing and capacity for locating thesepaths is still available. The power of the addressing spaces is alwaysfinite however, which rules out a full intermeshing of any number ofnodes with one another. Therefore the formation of signal paths fromdifferent transparent partial paths and the division of the transmissioncapacities using one of the multiple access methods mentioned above,cannot be ruled out in theory. In the following, with reference to FIGS.12 and 13, another embodiment of a network 10 according to the inventionwill be explained, for which, without limitation of generality, it isassumed that it consists of a transparent fully intermeshed "core" 1000with 3×3 nodes 1011 to 1013, 1021 to 1023, and 1031 to 1033, and ofanother eight nodes 1001 to 1008, by which this "core" 1000 has beenexpanded in the system shown. All the nodes of this network are linkedinto a lattice network by six optical fibers 1041 to 1046 and 1051 to1056 pairwise along lines 1014, 1015, 1016, 1017, and 1018 and alongcolumns 1024, 1025, 1026, and 1027. FIG. 13 shows an address table 1100that can be used to read the wavelengths of any node from which theother nodes of the network can be addressed that, looking in anydirection, are the closest or next to closest adjacent nodes of the(transmitting) node in question. The addressing takes place by analogywith the manner described in FIG. 8 where the address is encoded intoone of five different wavelengths I to V as well as fibers 1041 to 1046that are used to transmit the light flux affected by this wavelength. Incontrast to the embodiment explained with reference to FIGS. 7 and 8,however, the addressing of the adjacent nodes from this transmittingnode is always done according to a "practically fixed" address tablethat is the same for every node.

The choice of wavelength is made on the basis of address table 1100shown in FIG. 13. The choice of the fibers is very simple:

Fiber 1041 is used to address the "first right" adjacent column in FIG.12, fiber 1042 is used to address the next to adjacent right-handadjacent column, fiber 1044 is used to address the first left-handadjacent column, and fiber 1045 is used to address the next to adjacentleft-hand column. The allocation of the fibers along the columns is asfollows:

Fiber 1051 carries the data fluxes of the "first upper" adjacent line,fiber 1052 carries that of the "second upper" adjacent line, fiber 1054carries that of the "first lower" adjacent line, and fiber 1055 carriesthat of the "second lower" adjacent line to the receiving node inquestion.

of the fibers that are present within in a line or column, two fibersfor example fibers 1043, 1046, 1053, and 1056 are provided for loopingthe data fluxes through.

In the general case where network 10 comprises at least m columns and nlines that are fully intermeshed transparently with one another, and mis selected to be equal to or greater than n without limitation ofgenerality, (2·m-1) wavelengths defined as different and m·(m-1) opticalfibers are provided pairwise along the lines and columns between thenodes. This produces an addressing space as well as a supply of unusedtransmission capacity that permit any desired expansion of the number ofnodes that can communicate through a plurality of transparent wavelengthpaths with the expanded network so that as a result of the expansion,additional areas with a maximum of m×m nodes result that are fullyintermeshed with one another. The embodiment shown in FIG. 12 comprisesnodes 1011-1013, 1021-1023, 1031-1033 that are fully intermeshed withone another. It also comprises nodes 1001 to 1008 which aretransparently intermeshed with nodes 1011-1013, 1021-1023, 1031-1033that are fully intermeshed with one another, by fibers 1041-1046, thatconnect nodes 1003, 1004, and 1005 of column 1024 with nodes 1011, 1021,and 1031 of column 1025 and by fibers 1051 to 1056 that connect node1002 of line 1014 with node 1011 of line 1015 and by the fibers thatconnect nodes 1007 and 1008 of line 1018 with nodes 1031 and 1032 ofline 1017. This produces two additional "quadratic" transparently fullyintermeshed partial networks of 3×3 nodes each, one of which comprisesnodes 1003, 1011, 1012, and 1004, 1021, 1022 and 1005, 1031, and 1032,and the other comprises nodes 1004, 1021, 1022 and 1005, 1031, 1032, and1006, 1007, and 1008.

We claim:
 1. A transport network with a transmission capacity fortelecommunications in which nodes of the network are transparentlyconnected with one another by optical glass fiber lines functionally toproduce a full intermeshing of nodes permitting simultaneous addressingof all the nodes by every other node of the network comprising:(a) thenodes are coupled with one another in a matrix configuration in linesand columns; (b) each of corner nodes has at least n connections in thecolumn direction and at least m connections in the line direction: (c)intermediate nodes (1,2 to 1,(m-1); n,2 to n,(m-1)) that are located inmarginal lines, in a direction of the columns, have n connections and ina direction of the lines have 2·m connections, and the intermediatenodes (2,1 to (n-1),1 and 2,m to (n-1),m)) located in marginal columns,in a line direction, have m connections and, in a column direction, have2·n connections; (d) inner nodes of network are connected with each offour neighbors by a total of 2·m connections, in the line direction, and2·n connections, in the column direction; (e) individual nodes areaddressable by at least one line and/or one column; (f) a transmittingnode addresses the received node first by sending out informationthrough a fiber associated with a column of a receiver and secondly by asignal identifier associated with a line of a receiving node; (g) thereceiver identifies the line in which a transmitter is located from theoptical fiber through which signal light flux is conducted to it andidentifies a column of the transmitting node from the signal identifierof the received light flux; and (h) each node has (n·m-1) transmittersthat are operable with the corresponding signal identifiers and (n·m-1)receivers each of which responds to one of the m different identifierswhich are assigned to the nodes located in a line.
 2. A networkaccording to claim 1 wherein each node (n·m-1) has optical transmittersand receivers that are operable on different wavelengths, withaddressing being encoded into the different wavelengths.
 3. A networkaccording to claim 2 wherein time slots are associated with each node ina periodic sequence, within which each node is addressable by signalstransmitted by the other nodes.
 4. A network according to claim 3wherein an unambiguous combination of a wavelength and a time slot isutilized for addressing.
 5. A network according to claims 4 wherein thecombination of wavelengths and time slots for addressing, the time slotsare used only for addressing within a column and the data streams fromdifferent columns within a node are brought together only bypower-dividing elements.
 6. A network according to claim 2 wherein inthe event of a failure of a node (1,1 to n,m) or an optical glass fiberlink between two nodes, multiple protection paths can be connected.
 7. Anetwork according to claim 6, wherein the multiple protection paths canbe switched by means of an electronic control unit so that data fluxesthat were determined to pass a part of the network that has dropped out,from a respective sending node, with aid of a multiplex method, areadded to a data stream that is conducted to a network node of anotherline in order there again be added to another data stream by a multiplexmethod, said stream leading to the original destination nodes of abypassed protected data stream.
 8. A network according to claim 2wherein the nodes have a uniform integratable structure which has asmany wavelength multiplexers and wavelength demultiplexers as theoptical fibers and waveguides that are connected to it, and waveguidesconduct only light fluxes with one wavelength, that link the opticaloutputs of the wavelength demultiplexers with the optical inputs of thewavelength multiplexers.
 9. A network according to claim 8 wherein lightfluxes on the waveguides that link the wavelength demultiplexers and thewavelength multiplexers are reinforced with optical semiconductoramplifiers and are regenerated in their modulation pulse formation. 10.A network according to claim 1 wherein at least two additional opticalfibers can be connected from nodes other than those in the network to atleast one node of the network.
 11. A network according to claim 10wherein the network is operable with M different wavelengths in whichwavelength multiplexers and wavelength demultiplexers of the network areoperable with at least M+1 different wavelengths.
 12. A networkaccording to claim 11 wherein for all nodes in both the column and linedirections each time, at least N·(N-1) connections are provided and theaddress of the line of each node is encoded into one of at least 2·N-1different wavelengths defined for the nodes of the line, where N is thelarger of the two numbers n and m.
 13. A telecommunications network witha transmission capacity at nodes (1,1 to n,m) of the network are linkedtogether transparently with one another by optical glass fiber linesfunctionally to produce a complete intermeshing of nodes (1,1 to n,m)that permits a simultaneous addressing of all the nodes (1,1 to n,m) byevery other node in network comprising:(a) nodes (1,1 to n,m) arecoupled with one another in a matrix arrangement in lines and columns;(b) each corner node (1,1; 1,m; n, 1, and n,m) has at least nconnections in a column direction and has at least 2·m connections in aline direction: (c) intermediate nodes located in marginal lines (1,2 to1,(m-1) and n,2 to n,(m-1)) have at least n connections in the columndirection and have at least 2 m connections in line direction, and theintermediate nodes located in the marginal columns (2,1 to (n-1),1 and2,m to (n-1),m)) have at least m connections in a line direction andhave at least 2·n connections in the column direction; (d) inner nodesof the network are connected with each of four neighbors by a total ofat least 2·m connections in the line direction and by at least 2·nconnections in the column direction; (e) individual nodes areaddressable by at least one line and/or one column; (f) a transmittingnode addresses a receiving node first by emitting information through afiber that is associated with a column of a receiver and second by asignal identifier that is associated with a line of the receiving node;(g) the receiver identifies a line in which a transmitter is located onthe optical fiber through which the signal light flux is conducted tothe receiver and the column of the receiving node from the signalidentifier of the received light flux; (h) each node (n·m-1) hastransmitters that are operable with corresponding signal identifiers and(n·m-1) receivers that respond to each of the m different identifiersthat are associated with the nodes arranged in a line, characterized bythe following features:each of the corner nodes (1,1; 1,m; n,1 and n,m)has at least 2·(n-1) connections in the column direction and at least2·(m-1) connections in the line direction; the intermediate nodes (1,2;. . . ;1,j; . . . ;1,(m-1) and n,2; . . . ;n,j; . . . ; n,(m-1) withj=(2;3; . . . ; m-1)) located in marginal lines, have at least 2·(n-1)connections in the column direction and at least2·(m-j)·j+2·(m-j+1)·(j-1) connections in a line direction, and theintermediate nodes located in the marginal columns (2,1; . . . ;i,1; . .. ;(m-1),1 and 2,m; . . . ; 1,j; . . . ; (n-1),m) with i=(2;3; . . . ;n-1)) have at least 2·(m-1) connections in the line direction and haveat least 2·(n-i)·i+2·(n-i+1)·(i-1) connections in the column direction;and the inner nodes (i,j with i=(2;3; . . . ;n-1) and j=(2;3; . . . ;m-1)) of the network are connected with each four neighbors by a totalof at least 2·(m-j)·j+2·(m-j+1)·(j-1) connections, in the linedirection, and with at least 2·(n-i)·i+2·(n-i+1)·(i-1) connections, inthe column direction.
 14. A network according to claim 13 wherein anaddress of a line of each node is encoded into one of N differentwavelengths and each node is addressable at one of the different Nwavelengths for the nodes of a line, with N being the larger of the twonumbers n and m.
 15. A network according to claim 14 wherein anidentical structure is provided for all nodes to which fibers areattached that carry light fluxes, that lead to a column of the node, andto which those fibers are connected that carry those light fluxes thatare directed from the node outward to other columns of the network, andthe other fibers are looped through.
 16. A network according to claim 15wherein independently of whether addressing of a controlled node fromanother node in the network takes place by a primary selection of thecolumn and secondary selection of the line or by a primary selection ofthe line and secondary selection of the column of a target node, thetarget node is always addressable by the same wavelength.
 17. A networkaccording to claim 16 wherein:(a) the nodes of columns j and j+1 areconnected together pairwise with four additional fibers in the linedirection, with j=(1,3,5,7, . . . , m-3,m-1) for even-numbered m andj=(1,3,5,7, . . . , m-4,m-2,m-1) for odd-numbered m: and (b) the nodesof line i and i+1 are connected together with four additional fiberspairwise in the column direction, where i=(1,3,5,7, . . . , n-3,n-1) foreven-numbered m and i=(1,3,5,7, . . . , n4,n-2,n-1) for odd-numbered m.18. A network according to claim 16, wherein time slots are assigned tothe network in a period sequence within which the network is alternatelyswitched to alternate signal path combinations.
 19. A network accordingto claim 16, wherein at least two networks with an identified functionand an identical transmission capacity but with different guidance ofthe signal paths are provided that are operable either alternately orjointly.